MoreDefensiveDatasource

At the end of the previous month I wrote a posting on DefensiveDatasource class that can be used to associate ASP.NET’s GridView with collections containing objects of different types and based on one and the same base class. Dividing data into pages in GridView does, however, not succeed. An error message "The data source does not support server-side data paging" is displayed.

There is a simple solution to this problem. We have to create a new class conforming to the ICollection interface based on DefensiveDatasource. As we need to deal with DefensiveDatasource only in case of collections of the IList type, I restricted the collection selection of the new class so that only IList based collections can be submitted to the class as initial collections.

public class MoreDefensiveDatasource : DefensiveDatasource, ICollection
{
    private IList list;
 
    public MoreDefensiveDatasource(IList innerSource, IDictionary propertyFilter)
        : base((IEnumerable)innerSource, propertyFilter)
    {
        this.list = innerSource;
    }
 
    int ICollection.Count
    {
        get { return list.Count; }
    }
 
    void ICollection.CopyTo(Array array, int index)
    {
        this.list.CopyTo(array, index);
    }
 
    bool ICollection.IsSynchronized
    {
        get { return this.list.IsSynchronized; }
    }
 
    object ICollection.SyncRoot
    {
        get { return this.list.SyncRoot; }
    }
}

For more extensive collection support I recommend using the ICollection interface as a restriction.